The long-term objectives are to improve the treatment of children with specific language impairment through the evolution and rigorous assessment of new treatment procedures. A series of experimental studies will sample more rigorously than prior studies the spontaneous speech of children before and after treatment in order to determine whether treatment led to genuine advances in available language structures and also to the children's widespread, generalized use of these new language structures in ordinary conversational contexts. Through rigorous specification of comparable language targets the experiments will determine the relative efficacy of conversationally-based but explicit treatment as contrasted with conversationally-disembedded but equally explicit imitation training. Through internal analyses of learning across all phases of the experiments by both language-impaired and normal children improvements are anticipated in process models, in treatment efficiency, and in matching of individual children to appropriate treatment variations. The experiments will also assess directly the degrees to which language-impaired children and language-normal children learn in the same way and the same rates when learning opportunities are closely equated. In addition the project will assess the roles in language learning of target frequency and pretreatment comprehension levels. Finally, the project will explore effective ways of combining imitation procedures with conversational recast procedures.